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Nextcloud TalkMattermost
Free

Free and open source as part of a Nextcloud server you host.

 Freemium

The desktop client is free and open source. The Mattermost server has a free self-hosted…

Android, Web, Self-hosted Windows, macOS, Linux
  • Runs on your own server
  • Chat, calls and webinars in one app
  • The server is self-hosted, so message data never leaves your infrastructure
  • Server dropdown lets one client connect to several Mattermost instances
  • Needs a Nextcloud server to use
  • Setting up reliable video calls takes extra server work
  • Needs a Mattermost server, which is real infrastructure to run
  • Electron, so memory use is high for a chat client
Downloadable app, Web application, Self-hosted Downloadable app
Open source Open source
License not stated License: Apache-2.0
Account needed Account needed
Needs internet Needs internet

Checked September 23, 2026

Checked September 21, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.